Car Stereos: speaker buzz, butt connector, pioneer head unit

Question
I have a clarion pro audio DXZ825 head unit and I have pioneer 3 way speakers that were fairly inexpensive . the brands I don't think mater I only mention them for reference. I took the clarion deck out once with the intent to replace it with a pioneer head unit but but it didn't work. about 1 week later I noticed a strange buzz in my right front door speaker that hasn't been there ever before and I've had the speakers for 6 months. it only buzzes in that lone speaker and the buzz shuts itself off and on. I can shut it of by tapping on my dash or hitting a bump in the road.  I've checked my ground and all other connections and there totally fine.

Answer
Hi Will,

Keep looking. :)  Your issue is invariably a loose wire or connection somewhere.

The first step I7 would take would be to cut out the solder joint or remove the butt connector connecting the aftermarket harness to the car's harness and rejoining them.  Work outwards from there.

Justin